Bio-Ninja
by Kriegcast
Summary: Orochimaru once experimented with an organism created before the days of chakra. Able to absorb the traits of anything it comes in contact with, what happens when it is released into the world?
1. Chapter 1

Some time after the Sasuke Retrieval Mission:

Land of Sound, Hidden Sound Village, Underground Laboratory B2

Golden slit eyes watched as the small cell-culture dish was infused with a small sample of blood. The cells were taken from Jugo during one of his "episodes" and the blood was taken from Kabuto and purified. This particular cell-culture was already infused with DNA from Sakon and Ukon. This was the latest in a series of experiments attempting to create a method of absorbing bloodline traits.

Orochimaru's end goal was immortality, but a close second was the complete mastery of ninjutsu. Many techniques derived from bloodlines eluded him unless he possessed the body of a member of each clan. However, he could not remain forever and when he moved to a new host, he could no longer use those techniques. If this experiment succeeded, he would have a body that would not reject him and could assimilate new genetic traits with little difficulty. The key to this experiment was something he was leery of using, however.

Long ago, before the Sage of Six Paths and chakra, the Old World was consumed in a great disaster. Remnants survived and humanity had rediscovered some of the lost technology such as cameras, steam power, and computers. Orochimaru had found an artifact from that time, a relic of biology that was one-of-a-kind. Records found indicated it contained a dangerous substance, one that was originally derived from a fusion of bacteria and viruses. The intent was for it to cure certain diseases and genetic damage. However, the organism was flawed due to how much energy was necessary to propagate and enact repairs. When the organism could not sustain itself, it went dormant permanently and was no longer considered viable. The project was dismantled and the organism was locked away.

The Snake Sannin had found the last viable specimen. The other vials had been damaged, but one small vial survived. Filled with a grey gel, that vial was about to be added to the small cell culture before him. A few of his trusted scientists were assisting in making sure the culture was untainted by outside materials and preparing for future infusions once the organism had grown.

Orochimaru hoped that the combination of Jugo's ability to absorb nature chakra, Sakon and Ukon's ability to seamlessly fuse on a molecular level, and Kabuto's ability to quickly generate new cells would be enough to allow the organism to replicate. If successful, he would have a living mass of tissue that could be harvested and perfected, allowing for new genetic material to be replicated. Eventually, he might be able to grow a new body that would never reject him and could use techniques only accessible with the right genetic markers.

He and his scientists watched as the last sample of the organism was poured into the cell culture. Immediately, the tissue sample began expanding, quickly growing to the size of his fist, then a small animal, even bigger! The scientists stepped back as the mass began expanding rapidly, although one of them was a little too slow.

The unlucky scientist started screaming as the mass engulfed his right foot, slowly creeping up his leg while visibly changing form. Where before it was a shapeless mass of grey tissue, bony protrusions and veins now started forming across the surface. As for the hapless scientist being eaten alive, one of his fellow scientists used a wind jutsu and cut his right leg off before the organism could consume him. The others pulled him away as the organism paused, perhaps needing time to fully assimilate the new genetic material.

_It's certainly more impressive then I though. However, the nature chakra in this area was never plentiful to begin with. It will soon run out of energy and go dormant, so I need to seal it away until an alternative energy source can be found._ Perhaps a form of photosynthesis? Certain animals in nature have the ability to consume plant cells and make use of their photosynthetic abilities to supplement their normal food supplies. A reduced energy level would make the organism more manageable and hopefully prevent future accidents.

Orochimaru's introspection was cut short by a sudden surge of chakra. The injured scientist was forming hand signs, facing the resting organism. "No! You idiot, stop that at once!" He shouted, unleashing a wave of snakes from his sleeves, hoping to prevent a disaster. His snakes wrapped around the reckless scientist moments after he shot off a large fireball. The flames immediately consumed the mass of tissue, charring flesh and blackening bone. Watching in horror as his only specimen was burned to a pile of ash, he grit his teeth and hissed at the remaining scientists.

"Take that one to the holding cells. He will pay for ruining my experiment." He glared as they bound the one-legged scientist in sealing cuffs that prevented him from summoning chakra. As they carried him away, Orochimaru took one last look at his ruined masterpiece and stalked off to his private offices. As he left he called out to the retreating scientists. "And get someone to clean this up. Just dump it in the usual place."

About 10 minutes later, one of the many low-ranking genin that served as assistants in the laboratories arrived with a large plastic barrel. Shoveling the ash and chunks of bone into the barrel, he carried it down to the Pit.

The Pit was a deep, circular holding area for a particular group of Orochimaru's failed experiments. He kept them around to help dispose of waste materials. The creatures were originally kidnapped Akimichi clan members who were part of an experiment involving the Eight Gates. The Snake Sannin was attempting to permanently open at least some of the Gates without causing drastic injury and death, gaining the benefits without the drawbacks.

Akimichi clansmen were used to channeling large amounts of chakra as part of their clan techniques. It was thought that their bodies could sustain a constantly active Gate. The results were...less than ideal.

The first issue came up when the Akimichi method of body expansion activated due to the chakra usage. Normally, their clan techniques involved physically transforming their bodies using massive amounts of chakra converted from calories. Under the influence of an open Gate, however, their bodies randomly activated the expansion jutsu in parts of their bodies, forcing them to consume nutrients continuously to offset the expansion jutsu.

At first, soldier pills were used, but that grew too expensive, since the pills were not cheap or quick to produce. After that failed, the experiments began consuming anything within reach. Plants, rotten food, corpses, anything. Eventually, they were moved to the Pit and put to use consuming the remains of failed experiments. Or any poor sap who managed to annoy Orochimaru.

Over time, the misshapen creatures had become completely psychotic, the constant hunger and knowledge of what they had become driving the captured shinobi insane. Only pain, rage, and a mindless desire to eat remained. A few chunin guarded the rim of the Pit, using mud clones to manage the crazed monsters. They handled the creatures, dumping in refuse and objects better left to the imagination.

The Pit had another purpose: it was also where a small bolthole had been excavated. The tunnel led to a series of underground bunkers that contained food, supplies, and a source of fresh water provided by an underground river. A sealed door was put in place over the tunnel entrance although one of the misshapen behemoths had cracked it in a fit of rage.

It was to this area that the genin eventually arrived. Passing the plastic barrel to one of the chunin guards, he quickly left, not wishing to see the disgusting behemoths. The chunin tossed the barrel down to his mud clone and watched as one of the larger creatures, a former jonin if he remembered, quickly shambled over and swung at the clone with a massive arm. The clone crumbled under the force of the blow and the barrel shattered under the immense pressure.

A cloud of ash and bone fragments settled in a small pile and the behemoth quickly devoured everything it could, even licking up the powdery ash. The chunin watched idly as the beast gobbled up a rather large chunk of bone about the size of his fist. He turned back to a rather entertaining Icha Icha novel, only to look back as a horrifying mixture between a moan and a shriek erupted from the Pit. The chunin guards looked down and saw the former jonin thrashing about, grasping it's head in pain.

The creature roared and rammed the walls, causing the ground to shake. As the chunin guards began forming multiple mud clones, one of them ran over and activated an alarm, sending a signal to the rest of the facility. The mud clones tried to corral the beast using ninja wire but the Gate-enhanced Akimichi ignored them as it continued to go berserk.

Finally, it body-slammed the door to the underground bunkers, shattering it and the surrounding wall. A large cloud of stone fragments erupted, blocking the creature from view. As the guards waited for the cloud to clear, Orochimaru and a squad of jonin arrived. One of the chunin, who hid his Icha Icha novel before the Snake Sannin could see it, quickly explained the situation.

Thinking quickly, Orochimaru used a low-powered wind jutsu to clear the dust cloud. A pile of rubble comprised of door chunks and wall fragments blocked the entrance to the bolthole. The roaring of the monster was heard in the distance. A quick earth jutsu pushed the rubble aside and they all rushed down the tunnel.

A trail of broken stone led down to the underground bunkers. Partway down the tunnel, small blood spatters joined the trail of destruction caused by the behemoth. A long piercing shriek echoed throughout the bunker, cutting off with a gurgling noise. The other behemoths paused in their consumption for a few moments, looking toward the tunnel entrance, before going back to satisfying their insatiable hunger.

When Orochimaru heard the noise, he rushed ahead of his jonin squad. If what that chunin said was true, then his specimen may not have been completely destroyed. He spotted the beast face down at the edge of the underground river, head and shoulders submerged. Turning it over, he stared calmly at the gaping hole where the behemoth's face once existed.

Part of it's brain and skull remained. The rest looked as though something had eaten its way out of it's skull. He looked down into the water and considered his options. Obviously, something had survived of his original specimen. The organism had vanished into the depths of the river. He knew that river extended far underground, branching off into the Land of Fire, Land of Hot Water, and eventually the ocean near the Land of Whirlpools.

He knew there was no way to track the organism, much less retrieve it. He could only hope that it made its way into the depths of the earth with no way to replenish it's energy. Nature chakra

He turned back to the corpse of the behemoth. Looking at it's distended belly, he realized that at least some of the organism was ingested and could have remained in the stomach. The jonin squad that arrived found their leader leering over the corpse of the deranged behemoth, a sinister smile on his face.

Meanwhile, a lumpy mass of flesh tumbled along the bottom of the river, the current taking it deep underground...

A/N:

Okay, I know I haven't updated Yuiitsu-Shin in a while. I just had to get this thing out of my head and on to my computer.

The organism is roughly based on The Thing, Prototype's Blacklight Virus, and Naraku from Inuyasha.


	2. Chapter 2

It scurried along the ground, seeking a path to the next source of water. If Orochimaru could see his rogue specimen he would be shocked at the changes.

Far from the oblong mass of flesh that emerged from the behemoth's face, the organism now had a foot-long, cylindrical torso encased in rows of bone plates akin to the scutes found in some lizards. 6 spider-like legs emerged from large gaps in the bone plates, carrying it with ease over the often rough terrain. Smaller gaps running randomly along the creature's body served as openings for respiration and defense.

Such defenses were made obvious when a large snake attempted to attack the creature. Glands located directly beneath the gaps released a burst of hydrogen cyanide, a poisonous gas that drove back the snake. The creature turned to face the poisoned reptile.

At the center of 3 particularly large plates, a large gap served as the primary method of feeding on prey. Long filaments extended outward from the opening. Composed of the creature's original flesh, each was tipped with a needle-like fang that easily pierced the snake's scales. The creature moved in closer as the snake expired, more strands of flesh emerging to help in absorbing the snake's body.

Soon, the only thing left was a pile of scales. Bone, muscle, nerves, blood, everything was absorbed and used to supplement the low supply of nature chakra in the depths of the earth. Finished with its latest meal, the creature continued its journey to the next source of moisture.

Using olfactory senses fashioned after many of the blind cave animals, it located a pool of water that it had not encountered before. It moved down to the edge of the water and paused. A slight shudder went through the creature's frame as a section of bone on each side of the creature was re-absorbed and large gills formed. Thinner filaments without fangs extended out from the small gaps. As the creature made it's way to the bottom of the pool, the filaments caught detritus and small particles drifting through the water, allowing it to feed while underwater and on the move.

Although the underground river system extended deep beneath the earth, mining operations sometimes reached these depths. Having only animal instinct, the creature avoided human contact due to simple size differences and smell. It didn't truly understand its origins; it had no human intellect or sense of self for now.

The brain cells acquired from the behemoth and subsequent animals was not formed as a single organ. Rather, the cells were clustered in small groups around individual muscle groups and sensory organs. Until the various clusters grew large enough for more complex thoughts to occur, the creature was little more than an animal. Albeit, a dangerous animal that never stopped evolving.

Time Skip:

It has been 8 months since the creature first emerged from the behemoth. A massive increase in genetic material has come about from a gradual change in its environment. Pitch-black caves and underwater freshwater rivers had changed to a series of coastal cave systems, tidal pools and an ever-increasing saltwater mixture.

The creature had reached the coast.

At first, the increased saline content had hindered its progress, but the predation of organisms adapted to this mixture had alleviated any issues with iodine build-up. The additions of organs capable of processing blood as sustenance and glands able to produce a thick slime were put to good use as the creature's body had developed and grown. However, the biggest prize was the consumption of an unusual species of electric eel that lived in the brackish waters of the coastal cave system.

With the ability to release a short-range electric shock, the creature had moved on to tackling larger and more aggressive prey. It was not quite ready to venture out to the open ocean, but the shallow caves and tidal pools running along the eastern coast of the Land of Fire provided a perfect environment for it to thrive and evolve.

The local fishermen occasionally caught a glimpse of it, but never got a clear picture of the creature. The body profile would indicate a large lizard or perhaps a saltwater crocodile. Standing two feet tall and now 5 feet long, it gradually grew larger, not making many physical changes but increasing in size and length as it fed.

The bony scutes had remained but were now smaller and covered less surface area. A thin underlayer of cartilage encased the creature, allowing it more flexible movements. The multiple legs had vanished, replaced by four large, partially webbed feet. A single lung and a set of gills located behind the creature's head allowed it to continue to live on both land and water. The multiple eyes located at the head would be the first distinction from a normal creature. The small pores that once sheltered the underwater feeding filaments now covered most of its body. Each pore led to a poison gas-producing gland, a feeding filament, or a tube that could exude a thick slime.

A series of wide bumps ran along the creature's back, while a 3 foot tail dragged on the ground behind the torso. The bumps held organs that allowed for electric shocks to be produced, while the tail was completely prehensile and could whip around with ease. It had a blunted, flat tip and was made of alternating bands of cartilage and thinly covered muscles. The tail could be used for aquatic locomotion or defense, but the main purpose was the tooth-filled maw at the tip. Modeled after a lamprey, it could latch on to an animal and feed on it's blood.

The creature's head, which was essentially the same as a saltwater crocodile, had two forward facing eyes and a series of infrared-vision pits running the length of the head. Imitated from snakes, these pits allowed it to spot large animals such as humans and hide or flee before it could be noticed.

The jaws were comprised entirely of bone, but unlike a crocodile, there were no teeth. Instead, the jaws would latch on and organs located inside the upper jaw would immediately deliver a low-voltage electric shock that prevented escape and paralyzed its prey. Filaments located on the lower jaws would latch on and inject an enzyme that started breaking down the flesh of the prey, preparing it for digestion. They would also start harvesting the animal's blood.

The original organism fed by simply breaking down and consuming any cells it came in contact with. As it was exposed to alternate methods of feeding, it adapted those methods. It was more efficient to digest the flesh of an animal through a stomach and intestinal tract than it was to try and break down the material on a cellular level. This meant that the creature was no longer dependent on nature chakra.

An added benefit of this efficiency was that more energy could be used to increase the overall number of brain cells. It had not yet achieved full sentience and reason, but the increasing number of complex organs and muscles had necessitated a more complex network of neural filaments to coordinate movement, respiration, and predation. As opposed to a central organ like a brain, it had an interconnected network of nerve clusters that were gradually expanding as necessary. Sensations, a concept of self, self-awareness beyond the need to feed, these things were forming.

Luckily, Orochimaru had long since given up on trying to track down his wayward experiment or attempting to replicate it. The samples taken from the behemoth's stomach had been damaged due to the harsh acids in the human stomach. Most were rendered useless and the few cells he had managed to cultivate had been frozen for the time being. Besides, Sasuke Uchiha and his precious Sharingan held most of his attention.

A/N:

Yes, slow and a little too detailed, I know. Don't worry, there will be some action eventually, but writing this really is mostly for my own pleasure. The action will pick up in a couple of chapters if all goes well. And yes, my chapters are short. I don't really care.

Basic biology of the creature as of Chapter 1:

The original organism has the ability to make genetic changes on a cellular level to an existing DNA sample and repair damage, essentially getting rid of junk DNA or damage caused by disease or radiation or hocus-pocus, whatever you want to call it.

Thanks to Juugo's cells, it can process raw nature chakra and not run out of juice. Kabuto's rapid cell growth allows it to make changes to its genetic structure quickly. Sakon's ability allows it to take in foreign genetic material without rejecting it outright.

The creature's original problem is that if it runs out of energy, it will go dormant permanently. Nature chakra is not an infinite resource in the Naruto world, at least in most areas. So, it has begun emulating existing methods of feeding. The rapid cell growth seen in Chapter 1 was due to the large amount of nature chakra gathered and the relative simplicity of it's own cells.

As soon as it was introduced to more complex genetic material, like the poor scientist's leg, it paused as it tried to fully adapt the muscles, nerves, bones, etc.

As the creature moves through it's environment it gradually draws in the local nature chakra, but because it found itself in an area with such low amounts of nature chakra, it had to adapt to a lower level of activity and cell growth. Hence, no massive monstrosity of flesh like the Blob or something.


	3. Chapter 3

Land of Waves, 2 Years after Sasuke Retrieval Mission

It had learned much simply by watching the humans. But that was not enough. Watching them from the shadows created strange feelings. It didn't like those feelings. It didn't understand what those feelings were.

It was curious about the two-legged creatures that lived in it's territory. While it had consumed or driven off the other large predators, it held back from attacking the humans. Something about them called out to it. It had consumed one of them when it was younger, reacting in fear to a larger predator that had stepped on it while it was resting in the shallows.

From that event, it had created a humanoid form, mimicking their basic shape. It did not duplicate the consumed human, instead looking like a gray-skinned figure. It had no visible sex, the act of human reproduction being far inferior to it's own method of growth. Rather than hair, a multitude of green, segmented filaments extruded from it's skull gave it the appearance of thin dreadlocks flowing halfway down it's back. Green whorls and lines covered it's entire body.

While humans might see them as decorations or tattoos, the green pigment was actually the presence of chlorophyll. While in the ocean, the creature had indeed found an animal such as Orochimaru had once thought of. The animal, a type of sea slug, reused the photosynthetic cells of the algae that it consumed, supplementing it's food supply with energy from sunlight.

It's face was another area where it did not fully mimic the human form. It had two large golden eyes with slit pupils. The nose looked half-formed, with a multitude of small holes in place of nostrils. The mouth, at least, looked mostly normal, although the creature's teeth seemed exceptionally sharp.

It had the same number of fingers and toes as a human, but each appendage curved into a claw shape like a bird's, rather than ending in a finger or toe nail. Small protrusions jutted out from it's elbows. It was not tall, standing at only 5 and a half feet.

A multitude of thin white cords were wrapped around the creature's body in random patterns over it's body, almost like bandages. Made from a form of spider silk, it served as rudimentary clothing. This was yet another way the creature tried to copy the humans.

It hid beneath the docks and studied the humans and how they walked. Muscles in it's body twisted and contorted as it learned to balance on two feet and not four. It practiced speaking often, but the noises the humans made were just too complex. The fishermen became frightened of the strange noises echoing along the shoreline each evening.

It was this form that it created to try and interact with the humans. It wandered the shoreline of the Land of Waves, desiring to meet the humans but at the same time afraid of them. The more primitive, animal part of itself warned against this, but the new intelligence and curiosity that had only recently been born would not be denied.

It was this form that a young woman named Tsunami first met as she strolled along the beach behind her family's home. From that meeting came a slow, cautious relationship that extended to include the woman's son, Inari, and the woman's father, Tazuna. They slowly grew to welcome the creature, not fully understanding what it was but at the same time knowing that it was curious about humans and displayed no ill will towards them.

As time passed the creature learned, grew in intelligence and understanding of the world around it. It was the woman's son that gave the creature it's name, gave it an identity. He called it Niseru, meaning to copy or imitate, since it seemed to want to learn to be more human.

Inari took it as his responsibility to teach Niseru their language, which was a dialect of the common language spoken in the Elemental Nations. The Wave dialect was actually a mixture of Water and Whirlpool, due to Wave's geographic location. Most of the inhabitants hailed from the Land of Whirlpools or Land of Water originally, whether as refugees from the bloodline purges or descendants of the original inhabitants of Whirlpool before it's destruction.

Niseru slowly came to understand something of what he was, as well as the place he had claimed as his territory. He did not live with his friends, finding comfort in the ocean that had been his lifelong home. However, he would often visit his friends, eventually coming to consider them his family, his humans.

Time flows ever onward, and after a year had passed a disturbing rumor reached the Land of Waves. Apparently, a great disaster had struck the place where the hero of Wave lived. Niseru had learned from Inari that the hero, Naruto, lived on the mainland in a place called Konoha. Due to the rumors, Tazuna and many of the able-bodied workers from Wave had left for Konoha to lend their assistance. Inari, who was almost a teenager at that point, was an apprentice architect and engineer and accompanied his grandfather and the others, leaving Tsunami and Niseru behind.

Niseru was uncomfortable, as he had never experienced being separated from his family like this before. Tsunami did her best to reassure him, but it had been three days and he was getting restless. He had taken to following her around while she did the household chores. However, she had to make a trip into town and he was not comfortable with other people yet.

Tsunami started down the path to town, leaving Niseru to wait at the house. He usually climbed up on the roof to rest in the sun or went hunting while she was out, but he had detected a foreign scent while hunting near the Great Bridge. Tsunami had told him about a large caravan of traders visiting and not to worry, but this scent was dangerous. Blood, metal, fear and pain. Another scent was mixed in: some sort of insect pheromone in large quantities.

Tsunami's scream had him rushing down the path to town. As he neared the outskirts he spotted her backed up against a tree. A large group of humans surrounded her, mostly wearing dirty and rusty armor. Fifteen of them were wielding various weapons ranging from spears to swords, while the sixteenth stood back from the rest, garbed in a full-body coat with his hands hidden in long sleeves.

Niseru immediately grew clusters of spines on his forearms and threw out his arms. The spines flew forward, turning three of the bandits into pincushions, their bodies beginning to rot from the necrotic venom contained in the spines. He rushed forward, knocking another bandit aside as he quickly moved to protect Tsunami. The other bandits backed up, looking back at the one wearing the large coat.

"Take him." The words were spoken quietly, but the remaining 11 bandits turned to face Niseru with determination. The one he had rushed lay on the ground, his body broken from the force of Niseru's blow.

Niseru pushed Tsunami behind him, telling her in his halting voice to go back to the house. As she quickly fled, he focused all his attention on the humans threatening his family. Tsunami was family. Tazuna and Inari were family. He protected family. They were _his_ humans.

These humans staring at him were not family. One thing he had learned in his admittedly short life was if it was not family then it was an enemy. And in his mind, the mind of a creature that mimicked but was intrinsically _not human_, mercy was a foreign concept for an enemy.

They made Niseru angry. Anger was a new emotion for him, although Tsunami had explained it to him in the past. She told him that anger was natural, but having it explained and feeling it firsthand were completely different. It coursed through him, making him irrational. He wanted these humans to feel pain and fear. He wanted them to _suffer_.

As he heard them moving forward, he readied himself for the change into something more useful than the form he usually took. That form was for the benefit of his humans. They no longer looked at him in fear, despite knowing of his inhumanity. It was time to unleash his true nature, the monster he knew he could become if he chose. Niseru was glad that Tsunami had gone back home. He didn't want her to see this.

"You are all just meat. Nothing but food!" Niseru growled to them as his body started growing, shifting, _becoming_...

KC:BN

Tsunami, having barricaded herself inside the house, shivered as an unearthly roar filled the air. She knew that their new family member was not human, but hearing that awful sound, she realized that Niseru was truly something beyond their understanding. No matter how much they tried to pretend, he was not a human.

Nevertheless, Niseru, whatever he was, would remain with them. It was his nature; from what she had observed, Niseru had adopted Tsunami, Tazuna, and Inari, identifying them as family on an emotional level. Knowing this, she simply looked out a window towards where he was fighting those bandits. Where he was fighting to protect her.

And when he returned, she would not look at him in fear or flinch when he was near. She would trust Niseru.


End file.
